1. Field of the Invention
This invention relates to a method for increasing salivation for the treatment of xerostomia and more particularly to increasing salivation by means of a chewing gum or confectionery composition containing xylitol.
2. Description of Related Art
Xerostomia, dry mouth syndrome or hyposalivation, has been defined functionally as a reduction of unstimulated salivary flow by greater than fifty percent as described by J. L. Gilpin in JDH, March-April, 1989, pp. 111-114. Xerostomia is a subjective clinical symptom characterized by a less than a normal amount of saliva with no apparent boundary between normal and abnormal. Saliva is a fluid mixture containing secretions from the salivary glands (parotid, submandibular, and sublingual), and many smaller minor salivary glands embedded in the submucosa of the cheeks, lips, hard and soft palates, and tongue. Because of its frequent occurrence in the elderly xerostomia was formerly thought to be a normal part of the aging process. Subsequent studies, however, indicate that xerostomia occurs in all age groups. Systemic diseases, medications, radiation therapy, and/or immunosuppression are among the main causes of dry mouth in the elderly. Clinical signs of xerostomia include dry, smooth, shiny mucosa, epithelial atrophy, inflammatory fissuring, especially of the tongue, and rampant caries, particularly of the cervical third of the teeth. Xerostomic patients may experience symptoms such as burning sensations due to fungal infection, inflammation of the tongue, and/or glossodynia or painful tongue. Patients may complain of difficulty with speech, swallowing, or denture retention. Xerostomia patients may even experience taste alterations and report that food tastes bland and papery, or they may experience salty or other unpleasant tastes. Normal saliva contains electrolytes of sodium, potassium, calcium, chloride, bicarbonate, and inorganic phosphate. Some of these components have specific taste properties, such as sodium (salty), and potassium (bitter/salty).
Various therapeutic measures have been recommended for patients experiencing xerostomia. Some of these include frequent rinsing with saline solutions to keep oral tissue moist and healthy. Additionally, fluoride rinses and topical gels have also been used to protect existing dental enamel and avoid root caries. Besides rinses, artificial saliva and salivary substitutes have been proposed as a palliative treatment for patients with non-functional glandular tissue, which preparations have a viscosity and electrolyte composition that approximates whole saliva. The use of mints and chewing gum have also been recommended to patients with non-atrophied glandular tissue, including gustatory stimulants such as lozenges or masticatory stimulants such as sugar-free chewing gum. See MARKOVIC, et al., Gerodontology, Vol. 7, Number 2, 1988 p. 71-75.
Saliva stimulating chewing gum compositions have been reported in the past. For example, U.S. Pat. No. 4,088,788 issued May 9, 1978 to R. L. REAM, et al., discloses such a chewing gum composition. The composition of Ream et al. comprises at least 3 percent by weight of an organic acid in combination with acid saccharin as the active agents for stimulating salivation. The gum further contains gum base, sodium and potassium salts, flavoring, emulsifiers, softeners and sweeteners.
U.S. Pat. No. 4,568,537 issued on Feb. 4, 1986 to K. C. HOERMAN, et al., also discloses a chewing gum composition containing an organic acid, e.g. adipic acid, as the active ingredient for stimulating salivary flow upon chewing of the gum. Salivation is said to be stimulated to an extent in excess of that required to neutralize the acid. Failure to neutralize the acid would be detrimental to the user. The gum preferably contains a sugarless sweetener which can be a water-soluble bulking agent present in an amount from about 30% to 65% by weight of the chewing gum and may comprise a sugar alcohol selected from sorbitol, mannitol and xylitol or mixtures thereof.
U.S. Pat. No. 4,284,650 issued Aug. 18, 1981 to J. J. GOUPIL, is directed to an anticaries chewing gum composition comprising an alkaline earth free gum base, a water-soluble fluoride and 10-53% xylitol mixed with sorbose or sorbitol. Fluorine is taught to be the active anticaries agent, xylitol, sorbose and sorbitol are used merely as sweeteners.
U.S. Pat. No. 4,127,677 issued Nov. 28, 1978 to P. O. FRONCZOWSKI, et al., discloses a xylitol coated chewing gum for providing an intense instantaneous cooling effect.
U.S. Pat. No. 3,899,593 issued Aug. 12, 1975 to J. E. HAMMOND, et al., is directed to chewing gum containing large quantities (&gt;50%) of xylitol for imparting a pleasant cooling effect.
U.S. Pat. No. 4,000,320 issued Dec. 28, 1976 to KLOSE, et al., discloses a sugar sweetened chewing gum composition which comprises gum base, flavor and sugar wherein the improvement comprises adding xylitol to the chewing gum composition in amounts less than 50% by weight of total gum composition which is effective to extend the storage stability of the gum. This patent was reissued as U.S. Pat. No. 30,197 on Jan. 22, 1980 wherein the xylitol amount was limited to less than 10% by weight of the total gum composition.
U.S. Pat. No. 4,065, 578 issued Dec. 27, 1977 to REGGIO, et al., discloses a sugarless chewing gum in the form of a soft, moist, continuous cohesive gum, which comprises gum base, xylitol as a bulk filler and sweetener, and a hydrocolloid selected from the group consisting of xanthan gum or an alginate derivative of kelp as a binder to facilitate formation of the soft, moist, continuous cohesive gum, said hydrocolloid being present in an amount within the range of from about 0.03 to about 1.0% by weight of said chewing gum and wherein said xylitol is preferably present in an amount within the range of from about 50 to about 70% by weight.